Programa de Pós-Graduac ão em Engenheira de Biomateriais, Universidade Federal de Lavras, Lavras 37.200-000, MG, BrazilLaboratório de Nanotecnologia Nacional de Agricultura (LNNA), Embrapa Instrumentac ão, São Carlos 13.560-970, SP, BrazilDepartamento de Ciências dos Alimentos, Universidade Federal de Lavras, Lavras 37.200-000, MG, BrazilLaboratório de Materiais e Biossistemas (LAMAB), Departamento de Engenharia de Materiais, Universidade Federal da Paraíba, João Pessoa 58.100-100,B, BrazilDepartamento de Engenharia, Universidade Federal de Lavras, Lavras 37.200-000, MG, Brazil
r t i c l e i n f o
rticle history:eceived 5 August 2015eceived in revised form 17 October 2015ccepted 29 October 2015
a b s t r a c t
Blends of thermoplastic cornstarch (TPS) and chitosan (TPC) were obtained by melt extrusion. The effectof TPC incorporation in TPS matrix and polymer interaction on morphology and thermal and mechanicalproperties were investigated. Possible interactions between the starch molecules and thermoplastic chi-tosan were assessed by XRD and FTIR techniques. Scanning Electron Microscopy (SEM) analyses showed a
homogeneous fracture surface without the presence of starch granules or chitosan aggregates. Althoughthe incorporation of thermoplastic chitosan caused a decrease in both tensile strength and stiffness, filmswith better extensibility and thermal stability were produced.
In recent decades, the growing environmental awareness hasncouraged the development of biodegradable materials fromenewable resources to replace conventional non-biodegradableaterials in many applications. Among them, polysaccharides
uch as starches offer several advantages for the replacement ofynthetic polymers in plastics industries due to their low cost,on-toxicity, biodegradability and availability (Fajardo et al., 2010;imkovic, 2013). Corn has been the main source of starch commer-ially available. Other minor sources include rice, wheat, potatond cassava and starchy foods such as yams, peas and lentilsBergthaller, 2005).
Starch is composed of amylose and amylopectin with rela-ive amounts of each component varying according to its plantource As an example, cornstarch has about 28 wt.% amylose asompared to cassava starch with 17 wt.%. Film-forming, barrier
nd mechanical properties, as well as processing conditions, areependent on amylose to amylopectin ratio. In general, an increas-
ng amount of amylose improves the abovementioned properties
Starch-based films, however, are brittle and hydrophilic, there-fore limiting their processing and application. In order to overcomethese drawbacks, starch can be mixed with various synthetic andnatural polymers. These approaches are: multilayer structures withaliphatic polyesters (Martin, Schwach, Avérous, & Couturier, 2001),blends with natural rubber (Carmona, De Campos, Marconcini, &Mattoso, 2014) or zein (Corradini, De Medeiros, Carvalho, Curvelo,& Mattoso, 2006) and composites with fibers (Rosa et al., 2009).Another widely used approach to improve mechanical propertiesand processability of starch films is the addition of chitosan.
Chitosan, which is obtained by partial or total deacetylation ofchitin, is one of the most abundant polysaccharides in nature, anda promising material for the production of packaging materials dueto the attractive combination of price, abundance and thermoplas-tic behavior, apart from its more hydrophobic nature as comparedto starch. Moreover, chitosan is non-toxic, biodegradable, and hasantimicrobial activity (Matet, Heuzey, & Ajji, 2014).
Several studies investigated the use of starch and chitosan in the
production of biofilms (Bourtoom & Chinnan, 2008; Dang & Yoksan,2014; Fajardo et al., 2010; Kittur, Harish Prashanth, Udaya Sankar,& Tharanathan, 2002; Lopez et al., 2014; Pelissari, Grossmann,Yamashita, & Pineda, 2009; Pelissari, Yamashita, & Grossmann,
011; Tuhin et al., 2012; Xu, Kim, Hanna, & Nag, 2005). However,ince chitosan films are fragile and require plasticizers to reduce therictional forces between the polymer chains to improve mechan-cal properties and flexibility, addition of polyols such as glycerol
ay reduce this drawback (Leceta, Guerrero, & De Caba, 2013; Park,arsh, & Rhim, 2002; Srinivasa, Ramesh, & Tharanathan, 2007;
erch & Korkhov, 2011; Leceta et al., 2013). Furthermore, chi-osan hydrophobic nature and mechanical properties can also be
odified and improved through blends with poly(ethylene gly-ol), poly(vinyl alcohol), polyamides, poly(acrylic acid), gelatin,tarch and cellulose (Arvanitoyannis, Psomiadou, Nakayama, Aiba,
Yamamoto, 1997; Kuzmina, Heinze, & Wawro, 2012; Lee et al.,998; Zhai, Zhao, Yoshii, & Kume, 2004).
Most works related to the production of biodegradable filmsased on starch and chitosan are obtained by casting (Ibrahim, Aziz,sman, Refaat, & El-sayed, 2010; Leceta, Penalba, Arana, Guerrero,
De Caba, 2015; Sindhu Mathew, 2008; Xu et al., 2005). In mostf these studies, starch is pre-gelatinized prior to chitosan addi-ion and pouring into a mold. Such methods are not adequate toarge-scale production of films, therefore limiting their industrialpplication. On the other hand, processing of starch–chitosan byethods such as extrusion and injection molding have been rela-
ively neglected.In this work, cornstarch–chitosan blends were produced by
xtrusion so as to evaluate the effect of chitosan addition on blendorphology, and mechanical and thermal properties, envisioning
large scale, mass production material, for industrial packagingpplication.
. Experimental
.1. Materials
Chitosan with a molecular weight of 90–310 kDa and aegree of deacetylation of 75–85% was purchased from PolymarForatelza-CE, Brazil). Cornstarch, containing 70% amylose and 30%mylopectin (Amidex® 3001), was supplied by Corn Products BrasilBalsa Nova—PR, Brazil). Glycerol, and citric and stearic acid wereurchased from Synth (Rio de Janeiro, Brazil).
.2. Starch–chitosan blending by extrusion
Thermoplastic starch (TPS) was prepared from native corntarch:glycerol:water (60:24:15 wt.%). The thermoplastic chitosanTPC) was obtained from the physical mixture of chitosan pow-er, acetic acid, glycerol and water at the following proportions:7, 2, 33 and 50 wt.%, respectively. Glycerol was first added to chi-osan and a 2 wt.% acetic acid solution was subsequently added toorm a paste following the procedure described by Epure, Griffon,ollet, and Avérous, (2011) in order to obtain the TPC. Addition-lly, 1 wt.% of stearic acid and 1 wt.% citric acid were added to bothompositions as processing aid.
Each of these mixtures was pre-mixed manually and thenxtruded using a model ZSK18 co-rotating twin-screw extruderCoperion Ltd., SP, Brazil), with L/D = 40, screw diameterD) = 18 mm equipped with seven heating zones. The temper-ture profile (from the feeder to the matrix) and screw speedere: 120/125/130/135/135/140/140 ◦C and 300 rpm for TPS,
nd 108/90/90/100/100/110 ◦C and 200 rpm for TPC. The TPS/TPClends were prepared using 5 (TC5) and 10 (TC10) wt.% in the
bovementioned extruder with the following temperature profilend screw speed: 101/104/109/109/107/106/107 ◦C and 350 rpm.hese conditions were established based on previous workseported by our group (Carmona, Corrêa, Marconcini, & Mattoso,
lymers 137 (2016) 452–458 453
2015; Carmona et al., 2014; Sengupta et al., 2007; Giroto et al.,2015; De Campos et al., 2013).
Extruded polymers and blends were pelletized using an auto-matic pelletizer (Coperion Ltd., SP, Brazil), do produce 2-mm pelletsthat were subsequently extruded in a single screw extruder (AXPlasticos Ltda., São Paulo, Brazil) operating at 120 rpm and a tem-perature profile of 80/90/100 ◦C. This extruder is equipped with aslit die to produce sheets that were then hot-pressed into films ofabout 800 �m in thickness.
obtained using a FTIR model Vertex 70 Bruker spectrophotome-ter (Bruker, Germany). Spectra were recorded at a spectral rangebetween 3500 and 6000 cm−1 at a scan rate of 180 scans and spec-tral resolution of 2 cm−1. The FTIR spectrum was employed in thetransmittance mode. FTIR analyses were performed to study theeffect of the addition of thermoplastic chitosan in thermoplasticstarch, to verify possible interactions among starch, chitosan andglycerol.
2.3.2. X-ray diffraction (XRD)The crystal structures of TPS and blends with TPC were ana-
lyzed from diffraction patterns obtained on a model XRD-6000Shimadzu X-ray diffractometer (Shimadzu, Kyoto, Japan). Sampleswere scanned from 5 to 40 (2�) using a scan rate of 1◦ min−1. Thediffraction patterns were fitted using Gaussian curves, after peakdeconvolution using a dedicated software (Origin 8.0TM). Crys-tallinity index (CI) of TPC and blends were estimated based on areasunder the crystalline and amorphous peaks after baseline correc-tion. The IC of TPS was estimated as a function of the B and Vhcrystal form according to Hulleman, Kalisvaart, Janssen, Feil, andVliegenthart (1999).
2.3.3. Scanning electron microscopy (SEM) analysesQualitative evaluation of the degree of mixture (distribution and
dispersion of the TPC phase in TPS) was performed by using a modelJSM 6510 JEOL SEM, operating at a 5 kV. Samples were mountedwith carbon tape on aluminum stubs. Cross-sections of fracturedsamples were mounted with the cross-section positioned upwardon the stubs. All specimens were sputter-coated with gold in asputter (Balzer, SCD 050).
2.3.4. Thermogravimetric measurementsTG/DTG analyzes of the copolymers and blends were per-
formed on a TGA Q500 TA Instruments TG (TA Instruments, USA).Thermogravimetric curves were performed under synthetic airatmosphere. Approximately 6 mg samples were loaded to a plat-inum crucible heated at a heating rate of 10 ◦C min−1 from 25 to600 ◦C.
2.3.5. Film thicknessFilm thickness was measured using a digital micrometer (IP65
Mitutoyo) at five random positions. The mean values were used tocalculate barrier and mechanical properties.
2.3.6. Mechanical propertiesTensile strength, maximum elongation at break and elastic
modulus were measured using a model DL3000 universal test-ing machine (EMIC, São Paulo, Brazil). Tests were carried out
according to ASTM D882-09. Test samples of mid-section 15 mmwide; 100 mm long and 0.8 mm in thickness were cut from theextruded films. At least six samples were tested for each com-position. Clamp-to-clamp distance, test speed and load cell were
ig. 1. FTIR spectra of thermoplastic cornstarch (TPS), thermoplastic chitosan (TPC)nd TPS blends with 5 and 10 wt.% TPC (TC5 and TC10).
0 mm, 25 mm min−1 and 50 kgf, respectively. The tensile strength�max) was calculated by dividing the maximum force on the cross-ectional area and the percent elongation (ε) was calculated asollows:
(%) = d − d0
d0× 100 (1)
here d is the final displacement, d0 is the initial displacementclamp-to-clamp distance). The elastic modulus (ε) was deter-
ined from the linear slope of the stress versus strain curves.
.4. Statistical analysis
Data were subjected to analysis of variance (ANOVA) to deter-ine statistical differences. Multiple comparisons were performed
y the Tukey test using the Sisvar® statistical software (Version.4). Statistical differences were declared at p < 0.05.
. Results and discussion
.1. FTIR characterization
Fig. 1 shows the FTIR spectra corresponding to TPS and TPC asell as to TPS/TPC blends.
The FTIR spectrum of TPS film featured absorption bands corre-ponding to the functional groups of starch and glycerol, i.e., bandst 920, 1022 and 1148 cm−1 (CO stretching), 1648 cm−1 (boundater), 3277 cm−1 ( OH groups), 2914 cm−1 (CH stretching) and
423 cm−1 (glycerol). These results are similar to the ones observedn the literature (Kizil, Irudayaraj, & Seetharaman, 2002).
Similarly, TPC spectrum was similar to previous studies (Lopezt al., 2014; Pranoto, Rakshit, & Salokhe, 2005; Xu et al., 2005), inhich the band at 3300 cm−1, due to OH stretching, overlaps theNH stretching band, in the same region. A small peak at 1647 cm−1
hows attributed to C O (amide I) stretching, a peak at 1717 cm−1,ndicating the presence of carbonyl groups, and peaks at 2875, 1415nd 1150-1014 cm−1 which correspond to stretching of CH, car-oxyl ( COO ) and CO groups, respectively.
The FTIR spectra of TPS/TPC blends resembled the pure TPS film
Fig. 1). This is somewhat understandable since a small amountf thermoplastic chitosan was added to TPS. A similar behavioras observed in the literature with starch films plasticized with
.37–1.45 wt.% chitosan (Dang & Yoksan, 2014).
Fig. 2. X-ray diffraction patterns of thermoplastic cornstarch (TPS), thermoplasticchitosan (PTC) and TPS blends with 5 and 10 wt.% TPC (TC5 and TC10).
Despite the FTIR spectra of the blends show typical signals forboth components, i.e., starch and plasticized chitosan, these inter-actions were not significant enough to cause peak shifts, as seen inFig. 1.
3.2. X-ray diffraction (XRD) analyzes
X-ray diffraction patterns of TPS, TPC and TPS/TPC blends areshown in Fig. 2.
TPS films showed diffraction peaks and broad amorphous halo,a typical behavior of a semi-crystalline polymer with low degree ofcrystallinity. TPS films showed diffraction peaks (2�) at 13.7, 17.7,20.4, 21.1 and 29.9◦ (Fig. 2). Peaks at 13.7 and 21.1◦ are assigned tothe Vh-type crystals of amylose complexed with glycerol (Teixeiraet al., 2010), while the peaks at 17.7 and 29.9 belong to B-typecrystals, which may have been formed during storage (Dang &Yoksan, 2014). Additionally, the absence of A-type crystals, whichis characteristic of the cereal starches granules, evidences that thenative cornstarch structure was completely destructurized duringextrusion (Shi et al., 2006), as can also be observed in SEM charac-terization.
Mikus et al. (2014) stressed that the Vh-type crystallinity isinduced by heat treatment, where the interaction between thehydroxyl groups of the starch molecules are replaced by hydrogenbonds formed between the plasticizer and starch during processing.
XDR diffraction patterns of PS/TPC blends are similar to theTPS matrix. However, it can be observed that with increasing TPCamounts in TPS matrix, the V-type crystallinity peaks becomewider, which is due to the decrease in formation of glycerol-amylose complex because of the limited mobility of amylosemolecules. The same behavior was observed by Lopez et al.
3.3. SEM characterization
SEM micrographs of the surface and fracture surface of TPS filmsand blends with TPC are shown in Fig. 3.
The pure starch film (Fig. 3A) showed the cross-section showedthe absence of starch granules after processing, demonstrating theextrusion process completely destructurized the native cornstarchgranules. These observations are consistent with the results of X-ray diffraction. The same behavior was observed to thermoplastic
chitosan (Fig. 3B). However, there are small surface cracks, whichmay have been formed during the compression-molding step afterthe extruded films were formed as a consequence of the brittlenature of chitosan.
ig. 3. SEM micrographs of (A) TPS-fracture surface; (B) TPC-fracture surface; (C) TC
On the other hand, TPS/TPS blends (Fig. 3C–F) had a homoge-eous surface without cracks and with good structural integrity.
n certain localized positions of the films there were slight sur-ace irregularities that may be formed during extrusion, at theie/polymer contact surface, a defect somewhat similar to someurface defects known to happen during processing of certain poly-ers (Tadmor & Gogos, 2006).In Fig. 3C and D (fracture surface) show the presence of TPC
articles dispersed within the starch matrix. No disruption of thePS/SPC interface was observed. This shows that there is a relativelyood interfacial adhesion between the two components.
Similar results were reported by Salleh, Muhamad, andhairuddin (2009) to starch–chitosan films obtained by casting,
n which chitosan particles dispersed within the starch–chitosanatrix were observed.
.4. Thermogravimetric analyzes
TG curves and their first derivative (DTG) curves for TPS, TPCnd TPC/TPC blends are shown in Fig. 4A and B. From TG (Fig. 4A),nd DTG (Fig. 4B) curves the onset (Tonset) and endset (Tendset)emperatures for degradation of TPS and blends are shown inable 1.
The TG curve of TPS clearly shows a degradation to take placen three steps, ranging from 25–160 ◦C, 160–500 ◦C and 500–600,
espectively, due to the evaporation of free water (Pelissari et al.,009), evaporation of water (Cyras, Manfredi, Ton-That, & Vázquez,008) and decomposition of the starch of the previously formedesidue since an oxidative atmosphere (Pelissari et al., 2009) (Fig. 4).
Some gases such as CO2, CO, H2O, and other small volatile com-pounds are released during this stage along with carbonaceousresidue formation (Zhang, Golding, & Burgar, 2002).
TPS exhibited a steady weight loss from room temperature toabout 250 ◦C. This is due to release of adsorbed water during itscombustion and glycerol evaporation. Such phenomenon preventsthe distinction between the first and second TPS degradation phaseand causes higher weight loss in the first degradation phase.
The TG curve of TPC presents a weight loss in two steps: thefirst weight loss at 140–350 ◦C, with a reduction of about 4%, andthe second loss at 350–500 ◦C, with a 93% weight loss. A similarbehavior was observed by Neto et al. (2005). Furthermore, as shownin Table 1, the addition of chitosan did not significantly change thethermal stability of blends as compared to thermoplastic starchalone.
TPS/TPC blends (Fig. 4) showed a mass loss in the temperatureranges of 25–160 ◦C, 160–500 ◦C and 500–600 ◦C, respectively due
Table 2Mechanical properties of TPS, TPC and TPS/TPC blends with 5 and 10 wt.%TPC.
Film formulation Thickness (�m) Tensile strength (MPa) Elongation at break (%) Elastic modulus (MPa)
TPS 755 2.1 ± 0.3a 69 ± 16a 39.00 ± 0.01a
TC5 757 1.5 ± 0.2b 108 ± 15b 16.10 ± 0.06b
TC10 838 1.1 ± 0.2c 93 ± 3b 8.40 ± 0.01b
Values correspond to average and standard deviations of the mechanical properties. Two consecutive letters of the same type show that the values are not statisticallysignificant (p < 0.05) using Turkey test. Different letters indicate that the averaged values are statistically different at the same level of significance (p < 0.05).
F(
3
osbppt
sppsecl
ples displayed no agglomeration of chitosan within a completely
ig. 4. TG (A) and DTG (C) of thermoplastic cornstarch (TPS), thermoplastic chitosanPTC) and TPS blends with 5 and 10 wt.% TPC (TC5 and TC10).
.5. Mechanical properties
The tensile strength, elongation at break and elastic modulusf pure thermoplastic polymers and are shown in Table 2. Fig. 5hows representative stress–strain curves of these polymers andlends. These curves display the typical stress–strain behavior oflasticized starch-based polymers and blends in which the lowestart of the curve displays a plastic behavior at deformations lowerhan 1%, followed by a plastic zone until sample rupture.
According to Table 2, the tensile strength of the biofilms wasignificantly affected by the addition of thermoplastic chitosan. Theresence of TPC reduced tensile strength of the blends, which wasrobably due to their plasticizing capability. Results in Table 2 alsohow that the addition of chitosan led to a significant reduction in
lastic modulus (p < 0.05), corroborating the abovementioned dis-ussion in which chitosan acts as a plasticizer to TPS, thus formingess rigid films.
Fig. 5. Representative stress–strain curves of TPS, TPC and TPS/TPC blends with 5and 10 wt.% TPC.
The addition of thermoplastic chitosan significantly affected theelongation at break, as compared to TPS (Fig. 5). This elongationat break indicates that the flexibility and stretching of the filmsincreased with the addition of chitosan. The addition of TPC atconcentrations between 5 and 10 wt.% to TPS matrix did not signif-icantly differ. However, this represents an increase in elongationat break of 56 and 35%, respectively, when compared to pure TPS.A similar behavior was reported in the literature (Pelissari et al.,2009), in which the physical-chemical properties and the antimi-crobial activity of starch–chitosan films with oregano essential oilwere studied.
Several studies (Alves, Mali, Beléia, & Grossmann, 2007; Mali,Karam, Ramos, & Grossmann, 2004; Sobral, Menegalli, Hubinger, &Roques, 2001) reported that the addition of chitosan decreases theelastic modulus of the TPS/TPC blends. These authors reported thatthe addition of the plasticizer help the TPS matrix to become lessdense, thus facilitating the movement of the polymer chains andimproving the flexibility of the films. These results are consistentwith the literature because this increase in elastic modulus of theblends with respect to TPS is due to the presence of hydrogen bondsbetween the plasticizer and starch molecules as well as due to thepresence of Vh-type crystals as also pointed out by Mikus et al.(2014).
4. Conclusions
Results show that it was possible to successfully producecornstarch–chitosan blends by extrusion with a high dispersionand distribution degree of the TPC phase in TPS as observed byscanning electron microscopy analyzes. SEM micrographs showedblends with homogeneous surface, and the criofractured sam-
destructurized starch matrix. These blends also had good thermalstability in which the addition of chitosan produced more ther-mally stable films. Moreover, addition of 5 and 10 wt.% chitosan
ate Po
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cted as a plasticizer to TPS matrix, increasing the elongation atreak (elongation at break increased by 56 to 35%, respectively)nd decreasing tensile strength and elastic modulus. Therefore,he obtained blends have potential for applications in packaging,specially where a high output of processed polymer is required asompared to batch processing such as casting.
cknowledgment
The authors are grateful to Empresa Brasileira de Pesquisagropecuária (EMBRAPA) for the facilities and equipment.
eferences
lves, V. D., Mali, S., Beléia, A., & Grossmann, M. V. E. (2007). Effect of glycerol andamylose enrichment on cassava starch film properties. Journal of FoodEngineering, 78, 941–946. http://dx.doi.org/10.1016/j.jfoodeng.2005.12.007
rvanitoyannis, I., Psomiadou, E., Nakayama, A., Aiba, S., & Yamamoto, N. (1997).Edible films made from gelatin, soluble starch and polyols, Part 3. FoodChemistry, 60(4), 593–604.
ergthaller, W. (2005). Starch in food—Structure, function, and application.Starch—Stärke, 57(3–4), 173. http://dx.doi.org/10.1002/star.200590016
ourtoom, T., & Chinnan, M. S. (2008). Preparation and properties of ricestarch–chitosan blend biodegradable film. LWT—Food Science and Technology,41(9), 1633–1641. http://dx.doi.org/10.1016/j.lwt.2007.10.014
armona, V. B., Corrêa, A. C., Marconcini, J. M., & Mattoso, L. H. C. (2015). Propertiesof a biodegradable ternary blend of thermoplastic starch (TPS),poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA). Journal of Polymers andthe Environment, 23(1), 83–89. http://dx.doi.org/10.1007/s10924-014-0666-7
armona, V. B., De Campos, A., Marconcini, J. M., & Mattoso, L. H. C. (2014). Kineticsof thermal degradation applied to biocomposites with TPS, PCL and sisal fibersby non-isothermal procedures. Journal of Thermal Analysis and Calorimetry, 115,153–160. http://dx.doi.org/10.1007/s10973-013-3259-0
orradini, E., De Medeiros, E. S., Carvalho, A. J. F., Curvelo, A. A S., & Mattoso, L. H. C.(2006). Mechanical and morphological characterization of starch/zein blendsplasticized with glycerol. Journal of Applied Polymer Science, 101(6), 4133–4139.http://dx.doi.org/10.1002/app.23570
yras, V. P., Manfredi, L. B., Ton-That, M.-T., & Vázquez, A. (2008). Physical andmechanical properties of thermoplastic starch/montmorillonitenanocomposite films. Carbohydrate Polymers, 73(1), 55–63. http://dx.doi.org/10.1016/j.carbpol.2007.11.014
ang, K. M., & Yoksan, R. (2014). Development of thermoplastic starch blown filmby incorporating plasticized chitosan. Carbohydrate Polymers, 115, 575–581.http://dx.doi.org/10.1016/j.carbpol.2014.09.005
e Campos, A., Tonoli, G. H. D., Marconcini, J. M., Mattoso, L. H. C., Klamczynski, A.,Gregorski, K. S., et al. (2013). TPS/PCL composite reinforced with treated sisalfibers: property, biodegradation and water-absorption. Journal of Polymers andthe Environment, 21(1), 1–7. http://dx.doi.org/10.1007/s10924-012-0512-8
pure, V., Griffon, M., Pollet, E., & Avérous, L. (2011). Structure and properties ofglycerol-plasticized chitosan obtained by mechanical kneading. CarbohydratePolymers, 83(2), 947–952. http://dx.doi.org/10.1016/j.carbpol.2010.09.003
ajardo, P., Martins, J. T., Fucinos, C., Pastrana, L., Teixeira, J. A., & Vicente, A. A.(2010). Evaluation of a chitosan-based edible film as carrier of natamycin toimprove the storability of Saloio cheese. Journal of Food Engineering, 101(4),349–356. http://dx.doi.org/10.1016/j.jfoodeng.2010.06.029
orssell, P., Lahtinen, R., Lahelin, M., & Myllärinen, P. (2002). Oxygen permeabilityof amylose and amylopectin films. Carbohydrate Polymers, 47(2), 125–129.http://dx.doi.org/10.1016/S0144-8617(01)00175-8
iroto, A. S., De Campos, A., Pereira, E. I., Ribeiro, T. S., Marconcini, J. M., & Ribeiro,C. (2015). Photoprotective effect of starch/montmorillonite composites onultraviolet-induced degradation of herbicides. Reactive and FunctionalPolymers, 93, 156–162.
ulleman, S. H., Kalisvaart, M., Janssen, F. H., Feil, H., & Vliegenthart, J. F. (1999).Origins of B-type crystallinity in glycerol-plasticised, compression-mouldedpotato starches. Carbohydrate Polymers, 39(4), 351–360. http://dx.doi.org/10.1016/S0144-8617(99)00024-7
brahim, M., Aziz, A., Osman, O., Refaat, A., & El-sayed, E. M. (2010). Molecularspectroscopic analysis of nano-chitosan blend as biosensor. SpectrochimicaActa, A: Molecular and Biomolecular Spectroscopy, 77, 802–806. http://dx.doi.org/10.1016/j.saa.2010.08.007
erch, Garry, & Korkhov, Vadim. (2011). Effect of storage time and temperature onstruture, mechanical and barrier properties of chitosan-based films. EuropeanFood Research and Technology, 232, 17–22.
ittur, F. S., Harish Prashanth, K. V., Udaya Sankar, K., & Tharanathan, R. N. (2002).Characterization of chitin, chitosan and their carboxymethyl derivatives by
izil, Ramazan, Irudayaraj, Joseph, & Seetharaman, K. (2002). Characterization ofIrradiated Starches by Using FT-Raman and FTIR Spectroscopy. Agricultural andFood Chemistry, 50, 3912–3918.
lymers 137 (2016) 452–458 457
Kuzmina, O., Heinze, T., & Wawro, D. (2012). Blending of cellulose and chitosan inalkyl imidazolium ionic liquids. International Scholarly Research Network, 2012,9. http://dx.doi.org/10.5402/2012/251950
Leceta, I., Guerrero, P., & De Caba, K. (2013). Functional properties ofchitosan-based films. Carbohydrate Polymers, 93(1), 339–346. http://dx.doi.org/10.1016/j.carbpol.2012.04.031
Leceta, I., Penalba, M., Arana, P., Guerrero, P., & De Caba, K. (2015). Ageing ofchitosan films: Effect of storage time on structure and optical, barrier andmechanical properties. European Polymer Journal, 66, 170–179.
Lee, J. W., Kim, S. Y., Kim, S. S., Lee, Y. M., Lee, K. H., & Kim, S. J. (1998). Synthesisand characteristics of interpenetrating polymer network hydrogel composedof chitosan and poly(acrylic acid). Journal of Applied Polymer Science, 73,113–120.
Lopez, O., Garcia, M., Villar, M. A., Gentili, A. A., Rodriguez, M. S., & Albertengo, L.(2014). Thermo-compression of biodegradable thermoplastic corn starch filmscontaining chitin and chitosan. LWT—Food Science and Technology, 57(1),106–115. http://dx.doi.org/10.1016/j.lwt.2014.01.024
Mali, S., Karam, L. B., Ramos, L. P., & Grossmann, M. V. E. (2004). Relationshipsamong the composition and physicochemical properties of starches with thecharacteristics of their films. Journal of Agricultural and Food Chemistry, 54,7720–7725.
Martin, O., Schwach, E., Avérous, L., & Couturier, Y. (2001). Properties ofbiodegradable multilayer films based on plasticized wheat starch researchpaper. Starch—Stärke, 53(8), 372–380.
Matet, M., Heuzey, M.-C., & Ajji, A. (2014). Morphology and antibacterial propertiesof plasticized chitosan/metallocene polyethylene blends. Journal of MaterialsScience, 49(15), 5427–5440. http://dx.doi.org/10.1007/s10853-014-8255-7
Mathew, Sindhu, & Emilia Abraham, T. (2008). Characterisation of ferulic acidincorporated starch–chitosan blend films. Food Hydrocolloids, 22, 826–835.
Mikus, P. Y., Alix, S., Soulestin, J., Lacrampe, M. F., Krawczak, P., Coqueret, X., et al.(2014). Deformation mechanisms of plasticized starch materials. CarbohydratePolymers, 114, 450–457.
Neto, C. G. T., Giacometti, J. A., Job, A. E., Ferreira, F. C., Fonseca, J. L. C., & Pereira, M.R. (2005). Thermal analysis of chitosan based networks. Carbohydrate Polymers,62(2), 97–103. http://dx.doi.org/10.1016/j.carbpol.2005.02.022
Park, S. Y., Marsh, K. S., & Rhim, J. W. (2002). Characteristics of different molecularweight chitosan films affected by the type of organic solvents. Journal of FoodScience, 67(1), 194–197. http://dx.doi.org/10.1111/j.1365-2621.2002.tb11382.x
Pelissari, F. M., Grossmann, M. V. E., Yamashita, F., & Pineda, E. A. G. (2009).Antimicrobial, mechanical, and barrier properties of cassava starch–chitosanfilms incorporated with oregano essential oil. Journal of Agricultural and FoodChemistry, 57(16), 7499–7504. http://dx.doi.org/10.1021/jf9002363
Pelissari, F. M., Yamashita, F., & Grossmann, M. V. E. (2011). Extrusion parametersrelated to starch/chitosan active films properties. International Journal of FoodScience & Technology, 46(4), 702–710. http://dx.doi.org/10.1111/j.1365-2621.2010.02533.x
Pranoto, Y., Rakshit, S. K., & Salokhe, V. M. (2005). Enhancing antimicrobial activityof chitosan films by incorporating garlic oil, potassium sorbate and nisin.LWT—Food Science and Technology, 38(8), 859–865. http://dx.doi.org/10.1016/j.lwt.2004.09.014
Raquez, J.-M., Nabar, Y., Srinivasan, M., Shin, B.-Y., Narayan, R., & Dubois, P. (2008).Maleated thermoplastic starch by reactive extrusion. Carbohydrate Polymers,74(2), 159–169. http://dx.doi.org/10.1016/j.carbpol.2008.01.027
Rindlava, Å., Hulleman, S. H. D., & Gatenholma, P. (1997). Formation of starch filmswith varying crystallinity. Carbohydrate Polymers, 34(1–2), 25–30. http://dx.doi.org/10.1016/S0144-8617(97)00093-3
Rosa, M. F., Chiou, B., Medeiros, E. S. S., Wood, D. F., Williams, T. G., Mattoso, L. H. C.,et al. (2009). Effect of fiber treatments on tensile and thermal properties ofstarch/ethylene vinyl alcohol copolymers/coir biocomposites. BioresourceTechnology, 100(21), 5196–5202.
Salleh, E., Muhamad, I. I., & Khairuddin, N. (2009). Structural characterization andphysical properties of antimicrobial (AM) starch-based films. World Academy ofScience Engineering and Technology, 3(7), 392–400.
Sengupta, R., Chakraborty, S., Bandyopadhyay, S., Dasgupta, S., Mukhopadhyay, R.,Auddy, K., et al. (2007). A short review on rubber/clay nanocomposites withemphasis on mechanical properties. Engineering, 47, 21–25. http://dx.doi.org/10.1002/pen
Shi, R., Liu, Q., Ding, T., Han, Y., Zhang, L., Chen, D., et al. (2006). Ageing of softthermoplastic starch with high glycerol content. Journal of Applied PolymerScience, http://dx.doi.org/10.1002/app
Simkovic, I. (2013). Unexplored possibilities of all-polysaccharide composites.Carbohydrate Polymers, 95(2), 697–715. http://dx.doi.org/10.1016/j.carbpol.2013.03.040
Sobral, P. J. A., Menegalli, F. C., Hubinger, M. D., & Roques, M. A. (2001). Mechanical,water vapor barrier and thermal properties of gelatin based edible films. FoodHydrocolloids, 15, 423–432.
Srinivasa, P. C., Ramesh, M. N., & Tharanathan, R. N. (2007). Effect of plasticizersand fatty acids on mechanical and permeability characteristics of chitosanfilms. Food Hydrocolloids, 21, 1113–1122. http://dx.doi.org/10.1016/j.foodhyd.2006.08.005
Tadmor, Z., & Gogos, C. G. (2006). Principles of polymer processing (2nd ed.). New
Jersey: Wiley-VCH Verlag.
Teixeira, E. M., Lotti, C., Corre, Ana C., Teodoro, Kelcilene B. R., Marconcini, José M.,& Mattoso, L. H. C. (2010). Thermoplastic corn starch reinforced with cottoncellulose nanofibers. Journal of Applied Polymer Science, http://dx.doi.org/10.1002/app
/chitosan blend film formed under the action of irradiation. Carbohydrate
58 J.F. Mendes et al. / Carbohydr
uhin, M. O., Rahman, N., Haque, M. E., Khan, R. A., Dafader, N. C., Islam, R., et al.(2012). Modification of mechanical and thermal property of chitosan–starch
blend films. Radiation Physics and Chemistry, 81(10), 1659–1668. http://dx.doi.org/10.1016/j.radphyschem.2012.04.015
u, Y. X., Kim, K. M., Hanna, M. A., & Nag, D. (2005). Chitosan–starch compositefilm: Preparation and characterization. Industrial Crops and Products, 21(2),185–192. http://dx.doi.org/10.1016/j.indcrop.2004.03.002
lymers 137 (2016) 452–458
Zhai, M., Zhao, L., Yoshii, F., & Kume, T. (2004). Study on antibacterial starch
Polymers, 57, 83–88. http://dx.doi.org/10.1016/j.carbpol.2004.04.003Zhang, X., Golding, J., & Burgar, I. (2002). Thermal decomposition chemistry of
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